Currently known rod scraper constructions for hydraulic cylinders and the like typically utilize an elastomeric or metallic ring having at least one circumferential lip positioned for scraping a rod or other member movable axially through an aperture defined by the ring. Reference, for example, Tregonning, U.S. Pat. No. 4,461,486, issued Jul. 24, 1984; and Wyse, U.S. Pat. No. 4,577,363, issued Mar. 25, 1986. Reference also similar sealing ring constructions disclosed in Linne, U.S. Pat. No. 4,469,336, issued Sep. 4, 1984 to Caterpillar Tractor Co.; Reinsma et al., U.S. Pat. No. 5,460,678, issued Oct. 24, 1995 to Caterpillar Inc.; and dust seals available from Nok Corporation of Tokyo, Japan.
Problems encountered when using currently known rod scraper constructions include debris accumulation around the rod scraper lip that can ingress into the hydraulic cylinder as the rod or other member is retracted therein. Such debris that enters the cylinder can cause deterioration of primary seals located in the cylinder which can ultimately lead to rod and/or cylinder damage and possibly failure.
Additionally, rod scrapers having multiple circumferential lips have been found to have a tendency to trap oil that leaks outwardly past the primary seals of a hydraulic cylinder, which trapped oil when pressurized can force the rod scraper from its mounted position in a stepped opening or other location on the hydraulic cylinder head or other member.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.